Addressing scale-up challenges and enhancement in performance of hydrogen-producing microbial electrolysis cell through electrode modifications

Abstract

Bioelectrohydrogenesis using a microbial electrolysis cell (MEC) is a promising technology for simultaneous hydrogen production and wastewater treatment which uses electrogenic microbes. Microbial activity at the anode and hydrogen evolution reaction at the cathode can be controlled by electrode–microbe interaction and electron transfer. The selection of anode electrode material is governed by electrochemical oxidation of substrates and subsequent electron transfer to the anode. Similarly, a good cathodic material should reduce the overpotential at the cathode and enhance the hydrogen evolution reaction and H2 recovery. This review mainly focused on modifications in electrode materials and cheaper novel alternatives to improve the performance for MEC and overcome its scale-up challenges for practical applications. Performance of various anode and cathode materials based on Ni alloys, stainless steel, polyaniline, palladium, and carbon has been discussed. The scalability of the material should consider its inexpensive fabrication procedure and efficiency.